--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/sinfo/tkhstate/BedHeightsUtils.java	Tue Aug 14 11:06:00 2018 +0200
@@ -0,0 +1,92 @@
+/** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde
+ * Software engineering by
+ *  Björnsen Beratende Ingenieure GmbH
+ *  Dr. Schumacher Ingenieurbüro für Wasser und Umwelt
+ *
+ * This file is Free Software under the GNU AGPL (>=v3)
+ * and comes with ABSOLUTELY NO WARRANTY! Check out the
+ * documentation coming with Dive4Elements River for details.
+ */
+package org.dive4elements.river.artifacts.sinfo.tkhstate;
+
+import java.util.Collection;
+import java.util.TreeSet;
+
+import org.apache.commons.lang.ArrayUtils;
+import org.apache.commons.lang.math.DoubleRange;
+
+/**
+ * Helper functions for bed height calculations
+ */
+public final class BedHeightsUtils {
+
+    /**
+     * Get a union of all stations in a collection of bed heights
+     */
+    public static double[] extractStations(final Collection<BedHeightsFinder> bedHeightFinders) {
+
+        return extractStations(bedHeightFinders, false);
+    }
+
+    /**
+     * Get a union of all stations in a collection of bed heights
+     */
+    public static double[] extractStations(final Collection<BedHeightsFinder> bedHeightFinders, final boolean minMaxAware) {
+
+        final Collection<Double> allStations = extractStationCollection(bedHeightFinders, minMaxAware);
+        return ArrayUtils.toPrimitive(allStations.toArray(new Double[allStations.size()]));
+    }
+
+    /**
+     * Get a union of all stations in a collection of bed heights
+     */
+    public static Collection<Double> extractStationCollection(final Collection<BedHeightsFinder> bedHeightFinders, final boolean minMaxAware) {
+
+        if (!minMaxAware)
+            return extractStationCollection(bedHeightFinders);
+
+        final DoubleRange kmRange = extractMinimumStationRange(bedHeightFinders);
+
+        final Collection<Double> allStations = new TreeSet<>();
+        for (final BedHeightsFinder bhf : bedHeightFinders) {
+            for (final Double station : bhf.getStations())
+                if ((station.doubleValue() >= kmRange.getMinimumDouble() - 0.0001) && (station.doubleValue() <= kmRange.getMaximumDouble() + 0.0001))
+                    allStations.add(station.doubleValue());
+        }
+        return allStations;
+    }
+
+    /**
+     * Get a union of all stations in a collection of bed heights
+     */
+    public static Collection<Double> extractStationCollection(final Collection<BedHeightsFinder> bedHeights) {
+
+        final Collection<Double> allStations = new TreeSet<>();
+
+        for (final BedHeightsFinder bedHeight : bedHeights)
+            allStations.addAll(bedHeight.getStations());
+
+        return allStations;
+    }
+
+    /**
+     * Intersects all km ranges of a collection of bed heights
+     */
+    public static DoubleRange extractMinimumStationRange(final Collection<BedHeightsFinder> bedHeightFinders) {
+        DoubleRange kmRange = null;
+        for (final BedHeightsFinder bhf : bedHeightFinders)
+            kmRange = intersectRanges(kmRange, bhf.getKmRange());
+        return new DoubleRange(kmRange.getMinimumDouble() - 0.0001, kmRange.getMaximumDouble() + 0.0001);
+    }
+
+    /**
+     * Creates a range with the minimum overlapping of two ranges
+     */
+    public static DoubleRange intersectRanges(final DoubleRange a, final DoubleRange b) {
+        if (a == null)
+            return new DoubleRange(b.getMinimumDouble(), b.getMaximumDouble());
+        if (b == null)
+            return new DoubleRange(a.getMinimumDouble(), a.getMaximumDouble());
+        return new DoubleRange(Math.max(a.getMinimumDouble(), b.getMinimumDouble()), Math.min(a.getMaximumDouble(), b.getMaximumDouble()));
+    }
+}